Bertha Cut
A TriAx geocomposite enabled construction of aroad across highly saturated, and very weak, groundto provide access to a new community being builton the outskirts of Perth, Scotland.
Benefits
- Enabling road construction over weak soils, with average CBR values of less than 0.5%
- Delivering a technically-viable alternativeto conventional approaches
A section of the road between the A85 and Bertha Park runsin a cutting through an area of weak soils, with ground water lying above road level. Construction of a conventional capping layer, forming the foundation of the temporary access road and the permanent pavement, was unsuccessful, so an alternative was needed.
Field trials demonstrated that an aggregate layer, mechanically stabilised by incorporating a geocomposite of TriAx geogrid backed with a non-woven geotextile, combined with a new drainage regime, would overcome the extremely challenging ground and groundwater conditions. This layer provided sufficient support to carry light construction traffic and also allowed the permanent road to be built above without any issues.
